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pj5000 02-23-2009 07:25 AM

concrete floor cracking
Hi, my daughter owns a Florida bungalow built in the 50's. Our problem is the original concrete floor is cracking, about 1/8 an inch wide, and it's traveling from back of house to the front. It seems to start where an addition was put on and she says dampness comes up through it. Do I need to call a contractor or can it be fixed by us and how?

glennjanie 02-23-2009 10:31 AM

Welcome PJ:
You can fix the crack with an elastromeric caulk, pressure applied. Some caulks are Butyl-Rubber, Silicone or a new Self-leveling caulk (I can't remember the name).
Pressure caulking means, cut the tip off to the width of the crack, point the caulk gun twoard the end you're caulking to at a 45* angle, begin to press the trigger and move as the caulk begins to build up in front of the tip. This fills the crack to a greater depth and levels the top off with the tip.

yesitsconcrete 02-24-2009 03:11 AM

its doubtful this crack will widen & narrow much as the temp of the conc's fairly uniform inside a home,,, i'd rather see you install a closed-cell backer rod in the widen'd crk then apply a sealant to the recommended depth:width ratio & dimensions - polyurethane OR 100% silicone - the stuff's avail from any apron store :D

jdougn 02-24-2009 06:44 AM

If the only issue is moisture then go with what Glenn said and it will be better than good. Just don't be cheap on the caulk and make sure to keep the nozzle tight against the concrete so that it pushes the caulk way down in the crack.
just my .o2, Doug

yesitsconcrete 03-27-2009 06:30 AM

not being that familiar w/characteristics of caulk, sealants're designed to adhere to the sides of cracks,,, impo, caulk's not the mtl for this problem,,, polysulfide would be my choice - easy name to remember's ' sika ' - you won't find this stuff in any h/o apron store, either - look for a pro const supply house instead.

realize this reply's late BUT if may help someone in the future altho few seem to read archives believing, instead, their situations ' unique ' & they're ' entitled ' to quik answers,,, what a country ! ! ! :rolleyes:

just my $.03 :D

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